FIG. 5B is a timing diagram (not to scale) illustrating operation of an isolator when shorts repeatedly occur and then disappear so fast that they are not detected by the controller, according to an embodiment. That is, by the time the controller wakes up due to the short and attempts to verify the short, the short is gone. Thus the isolator never opens and the Ptest is never activated. Such intermittent shorts may be very quick in duration. They are generally not a problem unless they occur often, which may lead to a loss of communications. For example, at 552 there is a short and the current dramatically increases. At 554, the short goes away before the controller can verify. This corresponds to the No branch at step 422 in FIG. 4. The incident is designated as a false positive and at step 470, FalsePosCntr is incremented. In the example of FIG. 5B, another short occurs at 556 and again disappears at 558, and once again FalsePosCntr is incremented. Once the value of FalsePosCntr reaches a predetermined threshold (Yes branch at step 414), TimerAdj is incremented by XX μsecs, which results in shortening the time (ShortConfTmr) at step 418 that the controller is to wait (step 420) before again checking whether the short is still present in step 422. Eventually, the wait time ShortConfTmr may be so short that the controller will see the short and treat that event as regular short by taking the Yes branch from step 422.